US3568791A - Air ducting - Google Patents

Air ducting Download PDF

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Publication number
US3568791A
US3568791A US802184A US3568791DA US3568791A US 3568791 A US3568791 A US 3568791A US 802184 A US802184 A US 802184A US 3568791D A US3568791D A US 3568791DA US 3568791 A US3568791 A US 3568791A
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United States
Prior art keywords
noise attenuator
center body
air
noise
length
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Expired - Lifetime
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US802184A
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English (en)
Inventor
Russell E Luxton
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University of Sydney
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University of Sydney
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Publication of US3568791A publication Critical patent/US3568791A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/24—Means for preventing or suppressing noise

Definitions

  • a noise attenuator for inserting into the air duct 56, 35, ing of an air-conditioning or ventilating system which consists [56] of Cm of a section of air ducting divided into at least two channels which differ from one another in length by an odd number of UNITED STATES PATENTS halves or quarters of the wave length of the predominant 2,027,359 1/ 1936 Wood et a1. 181/33 sound wave which is to be suppressed or diminished.
  • AIR nucrmo This invention relates to air ducts such as those employed in air conditioning and ventilating installations in which a current of air is supplied through a duct or trunk to a room or other space.
  • Such ducts include various corners or bends between a fan which impels the air along the duct and an air delivery outlet.
  • the dominant frequency is the blade passage frequency of the fan, usually of the order of a few hundred Hertz.
  • Absorbent materials are only effective for near normal incidence at frequencies above about 1000 Hz.
  • two channels are provided about a profiled center body.
  • the path lengths along the center lines of the two channels differ by one-half half (or other odd number of halves) of the wave length of the blade passage frequency.
  • the outlet plane of the filter becomes a low impedance point when viewed from upstream.
  • the impedance mismatch between the bend and the duct therefore results in a poor power transfer to the downstream duct, that is, a high attenuation at the design frequency.
  • a low pressure loss may be obtained by suitable profiling of the center body and the walls of the bend.
  • air ducting in an air-conditioning or ventilating system in furnished with a noise attenuator comprising at least one section divided into at least two channels of different lengths.
  • a noise attenuator comprising at least one section divided into at least two channels of different lengths.
  • the length of the shorter channel should be approximately equal to one'quarter or another odd multiple of quarters of the predominant wavelength.
  • the device of the invention can be fitted in a rectilinear air duct, comprising a section of the latter divided into two or more channels of different lengths.
  • one channel may continue straight through from the inlet to the outlet of the section, while the other is slightly bulged away from the line of the first channel.
  • Such a device may be constructed by making one wall of a section of trunking convex and placing inside the said section a body which on one face will be parallel to the rectilinear part of the section and form a straight channel with the latter, while the other side is convex so as to form a curved channel of constant dimensions in conjunction with the convex opposite wall of the section.
  • any air-conditioning or ventilating system includes various bends in the line of the air trunking and the device of the invention may usefully be incorporated in one or more of such be'nds, thus avoiding an extra pressure loss penalty.
  • such bend or each such bend comprises two channels, one of which is substantially similar to a radiused bend and the other, which is somewhat shorter, comprises substantially a chord to such bend.
  • Such chord does not need to be a straight lineand usually, if straight for part or most of its length, will be curved at each end to merge into the air inlet and outlet connections at the ends of the bend.
  • the detailed shape of the channels is determined ultimately by the requirement that the air flow through the channel should be as smooth as possible and should not separate from the surfaces.
  • a device of the type just indicated can conveniently be constructed by providing a bend for an air duct made up from flat top and bottom plates separated from one another by front and rear sidewalls, the rear sidewall being substantially an arc and the front sidewall substantially a chord extending across said arc but curved at its ends. At each end of the device flanges or other means for connection to inlet and outlet air trunks are provided.
  • a specially shaped body Positioned inside the bend is a specially shaped body which, in conjunction with the front and rear sidewalls, will form two separate channels, one of which will be of substantially arcuate shape in plan (or in the form of an arc with straight extensions at its ends) and the other of which, as above indicated, will be curved at each end and substantially straight in the middle and which will be shorterthan the arcuate channel, preferably by one-half or the predominant wavelength of the sound to be attenuated.
  • FIGS. show longitudinal sections through different noise attenuators respectively in accordance with various preferred forms of the invention.
  • FIGS. 1 and 2 show noise attenuators set in rectilinear air trunking and incorporating center bodies of different shapes
  • FIGS. 3 and 4 show noise attenuators set into bends in air trunking and again show center bodies of different shapes.
  • the air inlet from a fan (which is not shown) is indicated at 10 and this is preferably furnished with a sound absorbing lining or jacket 11.
  • the downstream air outlet in each case is indicated at 12 and these air inlets and air outlets are separated in each case by a noise attenuator secured to such air inlets and outlets by flanges l3, 14 or in any other convenient manner.
  • FIG. 1 there is a rectilinear channel 15 and a curved channel 16 separated by a hollow sheet metal body 17, the channels 15 and 16 having the same cross-sectional dimensions throughout their lengths but differing from one another by one-half of a wave length of the predominant sound to be attenuated, or by some odd number multiple of one-half of such wave length.
  • FIG. 2 the channels are depicted at 18 and 19 and these are separated from one another by a central body 20 which may be moulded from acoustically absorbent material, or which may be hollow and of sheet metal construction.
  • the cross-sectionalv dimensions of one or both of the channels may vary along the length or lengths of the latter.
  • the bends of FIG. 3 and FIG. 4 while substantially similar in their outer arcs, differ from one another on their inner arcs.
  • the inner arc in FIG. 3 is a smooth curve while that in FIG. 4 has a fiat, which is paralleled by a flat in the surface of the central body 26.
  • the lengths of the shorter channel 15, 18, 21 or 24 may, in each case, by designated as x).
  • A is the wavelength of the dominant noise component to be suppressed and a is a prescribed constant. In most circumstances A is approximately equal to the velocity of sound in air divided .by the product of the number of blades in the fan impelling the air and the The length of the longer channel 16, 19, 22 or 25 should thenbe(a+/Q)t.
  • the prescribed constant a should be equal to N/4 where N is an odd number.
  • the central body may be built up in various ways.
  • It may be hollow and be built up fromsheet metal, plywood or other convenient materials.
  • the center body may be built up from a metal frame over which cloth is stretched.
  • the center body may be. filled with rockwool, fibre glass .wool, or other sound-absorbing materials.
  • One very suitable way of making suchbodies is to make a template of the desired plan shape thereof and then cut out a series of sheets of fibre glass board or other soundabsorbing sheet material which can be laminated together to form a rugged sound-absorbing center body.
  • the body has some sound-absorbing properties of its own but this is not essential.
  • the main sound attenuating effect is achieved through interference of sound waves with one another and is produced 'even if all surfaces are hard and fully sound reflecting.
  • the attenuation in the bend depends to some extent on the configuration of the upstream and downstream ducting.
  • the passages through the bend interact in such a manner that the bend presents a very high impedance to noise of the characteristic frequency and acts as an acoustic filter for the latter.
  • the sound power is reflected upstream towards the fan from the bend and thus it is desirable to precede the bend by a length of trunking lined with a material which is capable of absorbing sound energy.
  • the shape of the center body and the duct walls should be adjusted as far as possible to minimize pressure losses and reductions in the rate of air flow.
  • the invention makes it possible to eliminate package attenuators in most installations, while achieving an improved attenuation of fan noise and good air flow comparable with that obtainable by normal radiused bends and substantially better than that obtainable with mitre bends.
  • Further noise suppression may sometimes by achieved by having a change in the cross-sectional areas of the air inlet and outlet trunking. That is to say the openings at the two ends of the bend may be of different sizes.
  • a noise attenuator for insertion in the air ducting of an air-conditioning or ventilation system comprising a section of air ducting divided into at least two channels which differ from one anot er in length by an odd number of halves of the wavelength of the predominant sound wave which is to be attenuated, and a profiled center body positioned within the section and which divides the section into the two channels.
  • a noise attenuator as claimed in claim 4 in which the hollow body is filled with sound absorbent material.
  • a noise attenuator as claimed in claim 1 in which the center body consists of a metal frame over which cloth is stretched.
  • a noise attenuator as claimed in claim 1 in which the center body consists of a metal frame-over which cloth is stretched.
  • the profiled center body is cut from a series of sheets selected from the group consisting of sheets of fibre glass board and sheets of other sound absorbing sheet material, which sheets i are laminated together.
  • insert ---The sound power associated with this frequency is therefo reflected upstream of the filter where it must absorbed in a suitable length of duct (i.e., in duct having a length greater than half of the w length of the frequency) lined with an absorbin medium.--.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Duct Arrangements (AREA)
US802184A 1968-02-27 1969-02-25 Air ducting Expired - Lifetime US3568791A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU34220/68A AU431320B2 (en) 1968-02-27 1968-02-27 Improvements in air ducting

Publications (1)

Publication Number Publication Date
US3568791A true US3568791A (en) 1971-03-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US802184A Expired - Lifetime US3568791A (en) 1968-02-27 1969-02-25 Air ducting

Country Status (3)

Country Link
US (1) US3568791A (enrdf_load_stackoverflow)
AU (1) AU431320B2 (enrdf_load_stackoverflow)
GB (1) GB1259193A (enrdf_load_stackoverflow)

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038820A (en) * 1973-12-25 1977-08-02 Yamaha, Hatsudoki Kabushiki Kaisha Two-cycle engine wave interference muffler means
US4135600A (en) * 1976-01-19 1979-01-23 Trio Kabushiki Kaisha Loudspeaker system
US4287962A (en) * 1977-11-14 1981-09-08 Industrial Acoustics Company Packless silencer
US4346781A (en) * 1978-11-16 1982-08-31 Massachusetts Institute Of Technology Lined-duct acoustic filter
US4572327A (en) * 1984-11-07 1986-02-25 Tempmaster Corporation Sound attenuator
US4832312A (en) * 1987-09-26 1989-05-23 Robert Bosch Gmbh Magnetic valve
EP0521584A1 (en) * 1991-07-05 1993-01-07 Adrianus Jacobus Zwaan Sound-damping ventilating device
US5276291A (en) * 1992-07-10 1994-01-04 Norris Thomas R Acoustic muffler for high volume fluid flow utilizing Heimholtz resonators with low flow resistance path
FR2768219A1 (fr) * 1997-09-11 1999-03-12 Nicoll Raccords Plastiques Dispositif amortisseur acoustique pour entree d'air menagee dans la maconnerie d'un batiment
US5929396A (en) * 1997-07-29 1999-07-27 Awad; Elias A. Noise reducing diffuser
DE19849698A1 (de) * 1998-10-28 2000-05-04 Andreas Pfeifer Schalldämpfer
US6558137B2 (en) * 2000-12-01 2003-05-06 Tecumseh Products Company Reciprocating piston compressor having improved noise attenuation
US6607252B2 (en) 2001-09-04 2003-08-19 Ford Global Technologies, Llc Anti-vibration brake system
US6796859B1 (en) * 2000-11-16 2004-09-28 Bombardier Recreational Products Inc. Air intake silencer
US20040238271A1 (en) * 2003-05-30 2004-12-02 M & I Heat Transfer Products Ltd. Inlet and outlet duct units for air supply fan
US20050106044A1 (en) * 2003-11-17 2005-05-19 Hitachi, Ltd. Oil pump
US20060124385A1 (en) * 2004-12-10 2006-06-15 Ingersoll-Rand Company Modular pressure pulsation dampener
US20070034444A1 (en) * 2005-08-15 2007-02-15 Mk Seiko Co., Ltd. Reflecting plate type silencer pipe
WO2007121855A1 (en) * 2006-04-20 2007-11-01 Airbus Deutschland Gmbh Noise optimized air distributor
EP1916424A2 (en) * 2006-10-25 2008-04-30 Valeo Klimasysteme GmbH Ventilation system with sound barrier
US20080139107A1 (en) * 2006-12-07 2008-06-12 Mk Seiko Co., Ltd Ventilator
US20080271945A1 (en) * 2007-03-16 2008-11-06 Alfred Theodor Dyck Fan Powered Silencing Terminal Unit
US20090084450A1 (en) * 2007-09-28 2009-04-02 Shade W Norm Branching Device for a Pulsation Attenuation Network
US20090200103A1 (en) * 2006-10-27 2009-08-13 Airbus Deutschland Gmbh Sonic absorption device for an air pipeline of an aircraft, in particular of an air conditioning system of an aircraft
US20090270022A1 (en) * 2008-04-23 2009-10-29 Mukesh Kumar Climate control duct architecture for a vehicle
CN101121374B (zh) * 2006-08-07 2010-06-09 株式会社电装 车辆空气调节用的空气管道和车辆用空调器
US20110061967A1 (en) * 2007-03-16 2011-03-17 E.H. Price Ltd. Sound attentuator
US20120291896A1 (en) * 2007-09-28 2012-11-22 Shade W Norm Branching device for a pulsation attenuation network
US20140024303A1 (en) * 2012-07-20 2014-01-23 Visteon Global Technologies, Inc. Air conditioning system for motor vehicle
US20140127047A1 (en) * 2007-08-09 2014-05-08 Optimum Power Technology L.P. Pulsation Attenuation
US8783413B1 (en) * 2013-03-13 2014-07-22 Denso International America, Inc. Tuned shunt tubes for climate control air-handling systems
CN107631106A (zh) * 2017-08-24 2018-01-26 江西泰豪军工集团有限公司 排气管道及其消声方法
CN108042083A (zh) * 2018-01-09 2018-05-18 佛山市顺德区美的洗涤电器制造有限公司 内水管、洗碗机内胆、洗碗机底座及洗碗机
US10139126B2 (en) * 2016-10-11 2018-11-27 University Of Dammam Airborne noise reduction system and method
DE102018121855A1 (de) * 2018-09-07 2020-03-12 Vaillant Gmbh Lüftungssystem
CN113203163A (zh) * 2021-04-22 2021-08-03 宁波奥克斯电气股份有限公司 一种空调器的降噪控制方法、装置及空调器
FR3160760A1 (fr) * 2024-04-02 2025-10-03 Saint-Gobain Isover Installation de distribution d’un flux d’air comprenant un secteur d’atténuation acoustique.

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2237408B (en) * 1989-10-28 1993-03-31 Gilberts Valve assembly
GB2250356B (en) * 1990-11-30 1994-03-30 Sargents Acoustics Limited Improvements in or relating to ducting
DE10256771A1 (de) * 2002-12-05 2004-06-17 Bayerische Motoren Werke Ag Vorrichtung zur Schalldämpfung in einer fluidführenden Rohrleitung
DE10360839B3 (de) * 2003-12-23 2005-06-09 Naber Holding Gmbh & Co. Kg Rohrkrümmer zum Verbinden von Fluidleitungen
DE102012208708A1 (de) * 2012-05-24 2013-11-28 Kreuzinger + Manhart Turbulenz Gmbh Strömungskanalanordnung
DE102013224141A1 (de) * 2013-11-26 2015-05-28 Continental Automotive Gmbh Ventilvorrichtung
CN110614901A (zh) * 2018-06-19 2019-12-27 保时捷股份公司 用于机动车辆的空调系统

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Publication number Priority date Publication date Assignee Title
DE178815C (enrdf_load_stackoverflow) *
GB121212A (en) * 1918-01-14 1918-12-12 William Hooton Silencer for Engines.
FR602160A (fr) * 1925-08-18 1926-03-13 Dispositif d'échappement silencieux
US2027359A (en) * 1928-11-30 1936-01-07 Gen Motors Corp Muffler
FR869343A (fr) * 1939-05-04 1942-01-29 Eberspaecher J Silencieux, en particulier pour moteur à combustion interne
FR910922A (fr) * 1944-12-23 1946-06-24 Travaux Souterrains Dispositif de construction de canaux d'insonorisation
US2990906A (en) * 1958-10-08 1961-07-04 Koppers Co Inc Acoustic absorber
US3323305A (en) * 1964-10-16 1967-06-06 Gen Motors Corp Attenuating device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE178815C (enrdf_load_stackoverflow) *
GB121212A (en) * 1918-01-14 1918-12-12 William Hooton Silencer for Engines.
FR602160A (fr) * 1925-08-18 1926-03-13 Dispositif d'échappement silencieux
US2027359A (en) * 1928-11-30 1936-01-07 Gen Motors Corp Muffler
FR869343A (fr) * 1939-05-04 1942-01-29 Eberspaecher J Silencieux, en particulier pour moteur à combustion interne
FR910922A (fr) * 1944-12-23 1946-06-24 Travaux Souterrains Dispositif de construction de canaux d'insonorisation
US2990906A (en) * 1958-10-08 1961-07-04 Koppers Co Inc Acoustic absorber
US3323305A (en) * 1964-10-16 1967-06-06 Gen Motors Corp Attenuating device

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* Cited by examiner, † Cited by third party
Title
A.P.C. Application of Martin Serial No. 333,231, Published 5/18/1943 *

Cited By (52)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038820A (en) * 1973-12-25 1977-08-02 Yamaha, Hatsudoki Kabushiki Kaisha Two-cycle engine wave interference muffler means
US4135600A (en) * 1976-01-19 1979-01-23 Trio Kabushiki Kaisha Loudspeaker system
US4287962A (en) * 1977-11-14 1981-09-08 Industrial Acoustics Company Packless silencer
US4346781A (en) * 1978-11-16 1982-08-31 Massachusetts Institute Of Technology Lined-duct acoustic filter
US4572327A (en) * 1984-11-07 1986-02-25 Tempmaster Corporation Sound attenuator
US4832312A (en) * 1987-09-26 1989-05-23 Robert Bosch Gmbh Magnetic valve
EP0521584A1 (en) * 1991-07-05 1993-01-07 Adrianus Jacobus Zwaan Sound-damping ventilating device
US5276291A (en) * 1992-07-10 1994-01-04 Norris Thomas R Acoustic muffler for high volume fluid flow utilizing Heimholtz resonators with low flow resistance path
US5929396A (en) * 1997-07-29 1999-07-27 Awad; Elias A. Noise reducing diffuser
CN1093239C (zh) * 1997-07-29 2002-10-23 爱里亚斯·A·爱华德 减噪音的扩散器和减小噪音的方法
FR2768219A1 (fr) * 1997-09-11 1999-03-12 Nicoll Raccords Plastiques Dispositif amortisseur acoustique pour entree d'air menagee dans la maconnerie d'un batiment
DE19849698A1 (de) * 1998-10-28 2000-05-04 Andreas Pfeifer Schalldämpfer
US6796859B1 (en) * 2000-11-16 2004-09-28 Bombardier Recreational Products Inc. Air intake silencer
US6558137B2 (en) * 2000-12-01 2003-05-06 Tecumseh Products Company Reciprocating piston compressor having improved noise attenuation
US6607252B2 (en) 2001-09-04 2003-08-19 Ford Global Technologies, Llc Anti-vibration brake system
US20040238271A1 (en) * 2003-05-30 2004-12-02 M & I Heat Transfer Products Ltd. Inlet and outlet duct units for air supply fan
US6920959B2 (en) 2003-05-30 2005-07-26 M & I Heat Transfer Products Ltd. Inlet and outlet duct units for air supply fan
US7704061B2 (en) * 2003-11-17 2010-04-27 Hitachi, Ltd. Oil pump
US20050106044A1 (en) * 2003-11-17 2005-05-19 Hitachi, Ltd. Oil pump
US20060124385A1 (en) * 2004-12-10 2006-06-15 Ingersoll-Rand Company Modular pressure pulsation dampener
US20070034444A1 (en) * 2005-08-15 2007-02-15 Mk Seiko Co., Ltd. Reflecting plate type silencer pipe
US7503426B2 (en) * 2005-08-15 2009-03-17 Mk Seiko Co., Ltd. Reflecting plate type silencer pipe
WO2007121855A1 (en) * 2006-04-20 2007-11-01 Airbus Deutschland Gmbh Noise optimized air distributor
US7815012B2 (en) 2006-04-20 2010-10-19 Airbus Deutschland Gmbh Noise optimized air distributor
CN101791936B (zh) * 2006-08-07 2013-06-12 株式会社电装 车辆空气调节用的空气管道和车辆用空调器
US8146706B2 (en) 2006-08-07 2012-04-03 Denso Corporation Air duct for vehicle air conditioning and air conditioner for vehicle
CN101121374B (zh) * 2006-08-07 2010-06-09 株式会社电装 车辆空气调节用的空气管道和车辆用空调器
EP1916424A2 (en) * 2006-10-25 2008-04-30 Valeo Klimasysteme GmbH Ventilation system with sound barrier
CN101636594B (zh) * 2006-10-27 2013-03-06 空中客车德国运营有限责任公司 用于飞行器的空气管道的吸声装置
US20090200103A1 (en) * 2006-10-27 2009-08-13 Airbus Deutschland Gmbh Sonic absorption device for an air pipeline of an aircraft, in particular of an air conditioning system of an aircraft
US8210307B2 (en) * 2006-10-27 2012-07-03 Airbus Operations Gmbh Sonic absorption device for an air pipeline of an aircraft, in particular of an air conditioning system of an aircraft
US20080139107A1 (en) * 2006-12-07 2008-06-12 Mk Seiko Co., Ltd Ventilator
US20080271945A1 (en) * 2007-03-16 2008-11-06 Alfred Theodor Dyck Fan Powered Silencing Terminal Unit
US7806229B2 (en) * 2007-03-16 2010-10-05 E.H. Price Ltd. Fan powered silencing terminal unit
US20110061967A1 (en) * 2007-03-16 2011-03-17 E.H. Price Ltd. Sound attentuator
US8210308B2 (en) 2007-03-16 2012-07-03 E.H. Price Ltd. Sound attentuator
US20140127047A1 (en) * 2007-08-09 2014-05-08 Optimum Power Technology L.P. Pulsation Attenuation
US20090084450A1 (en) * 2007-09-28 2009-04-02 Shade W Norm Branching Device for a Pulsation Attenuation Network
US10174875B2 (en) * 2007-09-28 2019-01-08 Aci Services, Inc. Branching device for a pulsation attenuation network
US20100126607A9 (en) * 2007-09-28 2010-05-27 Shade W Norm Branching Device for a Pulsation Attenuation Network
US20120291896A1 (en) * 2007-09-28 2012-11-22 Shade W Norm Branching device for a pulsation attenuation network
US8608532B2 (en) * 2008-04-23 2013-12-17 Ford Global Technologies, Llc Climate control duct architecture for a vehicle
US20090270022A1 (en) * 2008-04-23 2009-10-29 Mukesh Kumar Climate control duct architecture for a vehicle
US20140024303A1 (en) * 2012-07-20 2014-01-23 Visteon Global Technologies, Inc. Air conditioning system for motor vehicle
US8783413B1 (en) * 2013-03-13 2014-07-22 Denso International America, Inc. Tuned shunt tubes for climate control air-handling systems
US10139126B2 (en) * 2016-10-11 2018-11-27 University Of Dammam Airborne noise reduction system and method
CN107631106A (zh) * 2017-08-24 2018-01-26 江西泰豪军工集团有限公司 排气管道及其消声方法
CN108042083A (zh) * 2018-01-09 2018-05-18 佛山市顺德区美的洗涤电器制造有限公司 内水管、洗碗机内胆、洗碗机底座及洗碗机
DE102018121855A1 (de) * 2018-09-07 2020-03-12 Vaillant Gmbh Lüftungssystem
CN113203163A (zh) * 2021-04-22 2021-08-03 宁波奥克斯电气股份有限公司 一种空调器的降噪控制方法、装置及空调器
FR3160760A1 (fr) * 2024-04-02 2025-10-03 Saint-Gobain Isover Installation de distribution d’un flux d’air comprenant un secteur d’atténuation acoustique.
WO2025210309A1 (fr) * 2024-04-02 2025-10-09 Saint-Gobain Isover Installation de distribution d'un flux d'air comprenant un secteur d'atténuation acoustique

Also Published As

Publication number Publication date
AU3422068A (en) 1970-07-30
GB1259193A (enrdf_load_stackoverflow) 1972-01-05
AU431320B2 (en) 1972-12-28

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